Didi Gregorius, considered Arizona’s shortstop of the future, has a right elbow injury that has prevented him from throwing or batting for the past month. Diamondbacks general manager Kevin Towers revealed the injury at a briefing with reporters Tuesday.

He said Gregorius felt discomfort in the elbow while working out a month ago in preparation for the World Baseball Classic. Gregorius was flown from his home in Curacao to Arizona, where an examination found a slight strain of the ulnar collateral ligament, Towers said.

There was no indication that Gregorius was injured before the trade and, indeed, he did not report any discomfort to the Reds. He was likely going to start the year in the minors anyway, but it has to be discouraging news when the guy you traded your top prospect for comes up achy the first day you lay eyes on him.